With the 551 Inductor EQ, Rupert Neve Designs is simultaneously taking a step forwards and a step backwards. Backwards in the sense that it draws on well-known 1970s designs and forwards in the sense that the 551 optimises the vintage circuits with the best components of today.The 551 was built around the custom transformer specially developed by Rupert Neve for the 500 format. The 3-band EQ offers an HF shelf/peak band, an LF shelf/peak band and a parametric mid band as well as an 80Hz LoCut filter.As with the legendary vintage predecessors of the 10XX series, the mids of the 551 are equalised using a coil filter. The advantage of an inductor circuit over a capacitor circuit is the incredibly musical sound it develops when it is driven into saturation. This allows the 551 to add unrivalled punch and personality to the signal that goes far beyond standard frequency processing.Q-factor:Basically, the filter quality of the mid band depends on the gain setting. In "MF Hi Q" mode, the Q factor of the mid-band is increased or the filter quality is reduced.